I think that a template similar to the {{Username}} template, where the reason changes based on the violation would be good. However, I would use a different design for it. The one that I like is this:
Hello, I noticed that your talk page violates the [[wikiHow:Talk Page Policy|Talk Page Policy]] because {{{1}}} Otherwise, your talk page design may be modified or deleted. Thank you, and if you need any help, feel free to ask me or the [[Help Team]].
The {{{1}}} changes based on which part of the policy is violated:
For Large Boarders:
your talk page border width is wider than (size). The talk page policy says that the width can’t be wider than (size). Could you please change the size of your boarders so that the width is (size) or lower?
For fonts:
the font has been changed. Could you please change the font to (whatever the allowed font types are)?
For different colored text:
the color of the text of the talk page messages has been changed. Could you please change the color of the messages back to black?
For obscured text:
the messages are being obscured by your page design. Could you please change your design so that the messages are not obscured?
And you can write other parts to depending on what the final version of the policy is.
I use this message with the two bottom ones, and it is pretty well received and works well. And if I do have to edit the talk page, then I normally say something like, “I fixed (the issue) for you. : )”
